body {
    font-family: 'Helvetica Neue', Arial, sans-serif;
    background-color: #f0f2f5;
    color: #333;
    margin: 0;
    padding: 0;
}

.container {
    max-width: 1600px;
    margin: 0 auto;
    padding: 20px;
}

header {
    text-align: center;
    margin-bottom: 20px;
    padding: 20px;
    background-color: #fff;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

header h1 {
    margin: 0;
    font-size: 2.5em;
    color: #0052cc;
}

.chart-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: 20px;
}

.chart-container {
    background-color: #fff;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    display: flex;
    flex-direction: column;
}

.chart-container.wide {
    grid-column: span 2; /* 销售额图表占据两列 */
}

.chart-container h2 {
    text-align: center;
    margin-top: 0;
    margin-bottom: 15px;
    color: #172b4d;
    font-size: 1.2em;
}

.chart-box {
    width: 100%;
    height: 400px;
    flex-grow: 1;
}

.placeholder {
    display: flex;
    align-items: center;
    justify-content: center;
    flex-direction: column;
}

.placeholder-text {
    font-size: 1.5em;
    color: #aaa;
}


footer {
    text-align: center;
    margin-top: 40px;
    padding: 20px;
    color: #666;
}
    